Galactic longitude vs. Galactic latitude distribution of the GALCEN sample superimposed on the 8 μm IRAC image of GLIMPSE-II (Churchwell et al. 2009). The red filled symbols indicate our selected sample with [M/H] < −0.7, the blue filled symbols with [M/H] > −0.7, and the open black symbols the full GALCEN sample. Circles denote galactocentric radii of 50, 100, and 150 pc, assuming R_⊙ = 8 kpc. The black asterisk show the GC field of Cunha et al. (2007), the black triangles those of Ryde & Schultheis (2015), and the black squares those of Rich et al. (2007).